// Copyright (C) 2010, 2011, 2012 GlavSoft LLC.
// All rights reserved.
//
//-------------------------------------------------------------------------
// This file is part of the TightVNC software.  Please visit our Web site:
//
//                       http://www.tightvnc.com/
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//-------------------------------------------------------------------------
//
package com.glavsoft.transport;

import com.glavsoft.exceptions.ClosedConnectionException;
import com.glavsoft.exceptions.TransportException;
import java.io.*;
import java.nio.charset.Charset;

public class Reader {

    final static Charset ISO_8859_1 = Charset.forName("ISO-8859-1");
    private final DataInputStream is;

    public Reader(InputStream is) {
        this.is = new DataInputStream(new BufferedInputStream(is));
    }

    public byte readByte() throws TransportException {
        try {
            byte readByte = is.readByte();
            return readByte;
        } catch (EOFException e) {
            throw new ClosedConnectionException(e);
        } catch (IOException e) {
            throw new TransportException("Cannot read byte", e);
        }

    }

    public int readUInt8() throws TransportException {
        return readByte() & 0x0ff;
    }

    public int readUInt16() throws TransportException {
        return readInt16() & 0x0ffff;
    }

    public short readInt16() throws TransportException {
        try {
            short readShort = is.readShort();
            return readShort;
        } catch (EOFException e) {
            throw new ClosedConnectionException(e);
        } catch (IOException e) {
            throw new TransportException("Cannot read int16", e);
        }
    }

    public long readUInt32() throws TransportException {
        return readInt32() & 0xffffffffL;
    }

    public int readInt32() throws TransportException {
        try {
            int readInt = is.readInt();
            return readInt;
        } catch (EOFException e) {
            throw new ClosedConnectionException(e);
        } catch (IOException e) {
            throw new TransportException("Cannot read int16", e);
        }
    }

    /**
     * Read string by it length. Use this method only when sure no character
     * accept ASCII will be read. Use readBytes and character encoding
     * conversion instead.
     *
     * @return String read
     */
    public String readString(int length) throws TransportException {
        return new String(readBytes(length));
    }

    /**
     * Read 32-bit string length and then string themself by it length Use this
     * method only when sure no character accept ASCII will be read. Use
     * readBytes and character encoding conversion instead.
     *
     * @return String read
     * @throws TransportException
     */
    public String readString() throws TransportException {
        // unset most sighificant (sign) bit 'cause InputStream#readFully
        // reads
        // [int] length bytes from stream. Change when realy need read sthing more
        // than
        // 2147483647 bytes lenght
        int length = readInt32() & Integer.MAX_VALUE;
        return readString(length);
    }

    public byte[] readBytes(int length) throws TransportException {
        byte b[] = new byte[length];
        return readBytes(b, 0, length);
    }

    public byte[] readBytes(byte[] b, int offset, int length) throws TransportException {
        try {
            is.readFully(b, offset, length);
            return b;
        } catch (EOFException e) {
            throw new ClosedConnectionException(e);
        } catch (IOException e) {
            throw new TransportException("Cannot read " + length + " bytes array", e);
        }
    }
}